One example of the radio communication systems is a mobile communication system such as a cellular telephone system. The mobile communication system has a function aimed for estimating the location of a user equipment device for the purpose of, for example, commercial services using location information, management of the own system, emergency location identification, and location identification of a user equipment device for legal reasons such as a criminal investigation.
The method of estimating the location of a user equipment device is disclosed in, for example, Non-Patent Document 2 (Chapter 4.3) and Non-Patent Document 3 (Chapter 4.3).
In the mobile communication system, movable base station devices such as femtocells (H(e)NB) or mobile relays (e)NBs may be used for improving radio access performance.
The above-mentioned methods of estimating the location of a user equipment device disclosed in Non-Patent Documents 2 and 3 are predicated on that the location of the base station device is evident. If a movable base station device is present as described above and its location is not evident, as disclosed in Non-Patent Document 4, a problem that the location of a user equipment device becomes difficult to be estimated arises.
The location of the base station device is not evident, and thus, the location of the base station device cannot be identified when a problem occurs in a radio network, causing a problem in system maintenance, such as longer time required to solve the above-mentioned problem.
The methods of estimating the location of a base station device are disclosed in, for example, Non-Patent Document 5 and Patent Documents 1 to 3. Non-Patent Document 5 discloses that the function of estimating the location of a user equipment device using a radio wave from another fixed base station device or the global navigation satellite system (GNSS) function are provided to a base station device, to thereby estimate the location of the base station device.
Patent Document 1 discloses the method of estimating the location of a base station device in a case where a user equipment device is in a coverage of specific femtocell can receive signals from a global positioning system (GPS) satellite and in a case where the user equipment device can detect other neighbor macro cells. Patent Documents 2 and 3 disclose the technologies of estimating, upon emergency call, a femtocell of which coverage a user equipment device is currently in, from the past in-area information.